I have a cement slab that is 12Lx30W. I want to build to roof over it. I was told I could use 6x6 support beams, 2x8 ledger, 2x6s for rafters and 1/2 inch plywood for the roof, it will also be shingled. The slope is 2 12. I live in Chicago and would like to know if these are accurrate sizes for this roof.
Speak to the building inspector or town engineer in your community.
As mentioned check with the building dept. It all seems very thin. The 6x6 support would depend on much of a span between support. You won't go too far with the 6x6 a 4x8 would be a better choice. You could still only go
4' between support. 2x6 even at 16OC seem small for the snow load on that flat of a roof. The ledger would depend on how it is fastened to the house, and the rafters will still need to be tied to the house. I know you can't use shingles on that flat a roof. Existing slab probably doesn't have footings. Around here anything tied to the house needs to be on footings so the frost doesn't move it. This can be done but you will need more research.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.